James Cook University
Rosemary Allison
1998
Native vegetation continues to be cleared for agriculture,
urbanisation and forestry in many regions of Australia, posing a
serious threat to remaining native vegetation and fauna. The
project's focus was to investigate patterns in vegetation and bird
associations within fragmented tropical woodlands in coastal north
Queensland. Variations in species composition were monitored during
the dry and wet season on the Burdekin River floodplain and in the
Bowling Green Bay National Park, north Queensland. The length of
the project was 10 months: September 1997 to June 1998.
One of the objectives was to determine whether species
composition and structural complexity of remnant vegetation
deteriorated in fragmented landscapes over time and as patch sizes
decreased. Vegetation surveys indicated that there was a
considerable amount of variability in plant species composition
throughout the study area. Structural complexity was the highest
for communities within the National Park, which was attributed to
the lengthy history of habitat disturbance on the floodplain. Also,
it appeared that structurally similar woodlands supported a similar
bird species composition, however, each contained a number of
species that were unique to them.
Changes within the communities investigated clearly had a
significant impact on their associated bird species. Within the
patch sizes encountered the type of vegetation, rather than the
size of remnant patches, determined species richness in woodland
communities. Habitat disturbance on the floodplain benefited mainly
large insectivorous and carnivorous birds, and as a consequence
many of the bird species found within these areas are a reflection
of their preference for open woodland communities. Surprisingly,
there was no evidence of the expected reduction in species richness
of particular guilds (groups of species that feed in the same way)
in the disturbed sites.
The findings of this project highlight the importance of
maintaining conservation areas outside National Parks. Regional
conservation of species diversity can only be effectively achieved
by the existence of both remnant patches of vegetation on the
floodplain and relatively undisturbed communities within the
National Park.
Supervisors
A/Prof Richard Pearson, James Cook University
Dr Robert Congdon, James Cook University
